WASHINGTON (AP) -- The White House has urged Ukraine to move swiftly to form a unity government and help restore order after a spate of deadly violence.

Months of protests turned violent this week, with scores killed in clashes between demonstrators and police.

Under a European-mediated plan, protest leaders and President Viktor Yanukovych agreed Friday to form a new government and hold early elections. Parliament slashed the president's powers and voted to release his chief rival, former Prime Minister Yulia Tymoshenko, from prison.

By Saturday, protesters had taken over the capital of Kiev and seized the president's office as parliament voted to remove him and hold new elections.

Yanukovych called it a coup and insisted he would not step down.

In urging calm, White House press secretary Jay Carney said the U.S. urged the prompt formation of a broad, technocratic government of national unity.

"We have consistently advocated a de-escalation of violence, constitutional change, a coalition government, and early elections, and today's developments could move us closer to that goal," Carney said in a statement. "The unshakeable principle guiding events must be that the people of Ukraine determine their own future."

The U.S. also welcomed Tymoshenko's release from a prison hospital.

"We continue to urge an end to violence by all sides and a focus on peaceful, democratic dialogue, working pursuant to Ukraine's constitution and through its institutions of government," Carney said, adding that the U.S. will continue to work with its allies, Russia, and European and international organizations "to support a strong, prosperous, unified, and democratic Ukraine."

Protesters took to the streets of Kiev late last year after Yanukovych abandoned an agreement that would have strengthen his country's ties with the European Union in favor of seeking closer cooperation with Moscow.

Carney said the Ukrainian people should know that the U.S. values its long-standing ties with their country and will support them as they pursue democracy and economic development.

Secretary of State John Kerry and Russian Foreign Minister Sergey Lavrov agreed on the need to resolve the situation without violence when they spoke by phone Saturday afternoon, the State Department said in a statement.

Kerry "expressed the importance of encouraging Ukraine to move forward on a path towards constitutional change, de-escalation, the creation of a coalition government, early elections and rejection of violence," the State Department said in describing the call.

Meanwhile, Russia accused Ukraine's opposition of failing to fulfill its side of a peace deal. The Russian Foreign Ministry, meanwhile, said Lavrov told Kerry that opposition supporters had refused to surrender their weapons and effectively have taken the Ukrainian capital under their control.

In speaking with his German, French and Polish counterparts, Lavrov urged them to use their influence with the Ukrainian opposition, which he said "not only has failed to fulfill any of its obligations, but keeps making new demands under the influence of armed extremists and rioters." Their actions "pose a direct threat to Ukraine's sovereignty and constitutional order," he said.